An operator may place pieces of media on the flatbed surface in order to print images on the pieces according to digital images which have been offered to the control unit. Positioning of a piece of media must be done very accurate with respect to its position and orientation. The operator usually measures right-angled distances of the piece of media from the edges of the flatbed surface by a measuring tool like a measuring cord, a tape-measure or a ruler. Another method to position the media is to align the piece of media with reference rules which have been printed on the flatbed table beforehand. The operator enters the measured distances by means of an application running on a computer connected to the control unit of the flatbed printer or on the control unit itself. After entering the distances, the operator selects the digital image to be printed on the piece of media and start the printing of the flatbed printer. Therefore the control unit or the computer is provided with a user interface suitable for data entry in general. Resuming, the operator has to execute different manual steps. Each step may lead to operator errors before printing the digital image on the piece of media. To make it even more complex pieces of media may be placed on the flatbed table that have different thicknesses. The thickness of a piece media is measured from the flatbed surface in the direction perpendicular to the flatbed surface. The different thicknesses of the pieces of media lying on the flatbed surface of the flatbed printer may lead to dangerous situations, for example the print head may touch one of the pieces of media if it is higher than a piece of media that has just been printed upon and the print head has not yet been lifted to an appropriate height from the flatbed surface in order to print the higher piece of media.
It is an object of the present invention to achieve a method for error free printing of a plurality of media pieces of different thicknesses by means of a flat bed printer.